Was in a camping store yesterday & asked the bloke there what was happening with them.
He said that there's a slightly modified design been approved & starting to come back in - thinks Kmart / Target may have them already.
Apparently, the problem was with the little sprung clip that goes down into the cut-out on the neck of the gas bottle. If the bottle overheats, the neck is supposed to expand, pushing that little metal tongue up, which turns the flame off. On some units, it was found that the tongue was too soft, so that it would bend in place, rather then flipping upward, so flame kept burning while gas is pouring out of ruptured bottle
Have checked ours, & the clip is nice & stiff on both of them, so will continue to use them, making sure not to overheat the cylinder by putting too big a pan on top!